EGUsphere EGUsphere EGUsphere EGUsphere Copernicus Publications Göttingen, Germany 10.5194/egusphere-2023-2463 The Polar Radiant Energy in the Far Infrared Experiment (PREFIRE) principal component-based cloud mask: A simulation experiment Kahn Brian 1 Bertossa Cameron 2 Chen Xiuhong 3 Drouin Brian 1 Hokanson Erin 4 Huang Xianglei https://orcid.org/0000-0002-7129-614X 3 L'Ecuyer Tristan https://orcid.org/0000-0002-7584-4836 2 5 Mattingly Kyle https://orcid.org/0000-0002-7384-0903 4 Merrelli Aronne https://orcid.org/0000-0002-5138-8098 3 Michaels Tim 4 Miller Nate 4 5 Donat Federico 6 Maestri Tiziano https://orcid.org/0000-0001-9582-5029 6 Martinazzo Michele 6 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109, USA Department of Atmospheric and Oceanic Sciences, University of Wisconsin–Madison, Madison, Wisconsin, USA Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA Space Science and Engineering Center, University of Wisconsin–Madison, Madison, Wisconsin, USA Cooperative Institute for Meteorological Satellite Studies, Madison, Wisconsin, USA Physics and Astronomy Department, Alma Mater Studiorum – University of Bologna, Italy 08 11 2023 2023 1 31 Copyright: © 2023 Brian Kahn et al. 2023 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2463/ The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2463/egusphere-2023-2463.pdf

<div class="page" title="Page 1"> <div class="layoutArea"> <div class="column"> <p>We describe a cloud mask simulation experiment developed for the PREFIRE mission. The basis of the cloud mask is a principal component (PC) methodology (PC-MSK) adapted from the algorithm heritage of the upcoming Far-infrared Outgoing Radiation Understanding and Monitoring (FORUM) mission. Simulated clear-sky and cloudy-sky PREFIRE radiances are calculated from the Goddard Earth Observing System (GEOS) meteorological fields and include a variety of complex cloud configurations. The simulation experiment is based on local training that is adjusted along segments of simulated orbits that mimic actual PREFIRE orbits. A numerically stable method of separating clear sky from cloudy sky is achieved using Otsu&rsquo;s binary classification method and requires no a priori thresholding estimate for multimodal histograms. Comparisons are made against a machine-learning cloud mask (ML-MSK) developed for the PREFIRE mission. The global hit rate of PC-MSK (92.6 %) compares favorably to the hit rate of ML-MSK (95.3 %). The Arctic hit rate of PC-MSK (86.7 %) compares favorably to the hit rate of ML-MSK (89.4 %) and both cloud masks are shown to meet mission requirements for PREFIRE cloud detection. The simulation experiment demonstrates the potential for accurate cloud masking with PREFIRE despite a low number of information-containing PCs compared to those obtained from hyperspectral infrared sounders. We conclude with a discussion about clear-sky and cloudy-sky training sets that are suitable for an operational version of PC-MSK and their development during the post-launch checkout time period.</p> </div> </div> </div>